비전을 실현하기 위한 5g 무선통신기술 웹...
TRANSCRIPT
5G 비전을 실현하기 위한 5G 무선통신기술 웹 세미나
Agilent’s Electronic Measurement Group is now Keysight Technologies.
Keysight Technologies Inc. is the world's leading electronic measurement company, transforming today's measurement experience through innovation in wireless, modular, and software solutions. The company's 9,500 employees serve customers in more than 100 countries. Visit us at www.keysight.com, Call to 080-769-0800
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Agenda
– Modeling and evaluating multiple waveform techniques
– What do you need for mmWave MIMO radio channel study?
– Multi-Antenna Techniques
© Keysight Technologies 2015 3
Keysight EEsof EDA
Asia Market Development Manager 이 준 부장
Keysight EEsof EDA
Application Engineer 조 성원 부장
Part I. Modeling and evaluating multiple waveform techniques
Keysight EEsof EDA
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5G Enabling Devices >> Research Challenges
© Keysight Technologies 2015 5
Multi-band • Traditional cellular bands <6GH
• WiFi, BT, GNSS bands
• 5G mmWave bands
Multi-antenna • Impedance matching
• Mutual coupling
• Multi-band, multi-RAT port
sharing
• FD / Massive MIMO
Amplifier • Envelope tracking
• Digital predistortion
• Wide, multi bands
Multiple radio technologies • GSM/EDGE/WCDMA/HSPA/LTE
• WiFi/BT/WiGig/GNSS/5G
Advanced signal processing • Multiple MIMO modes and beamforming
• Network interference suppression
• Adaptive channel estimation / equalization
Full duplex communications • Self interference cancellation
• Dual polarization antenna
• Real time operation
New waveforms • Legacy OFDM enhancement
• FBMC, GFDM, UFMC
Multiple Access • Non-orthogonal
multiple access
• Random / scheduled /
hybrid
• Reference IPs
• Evaluate in multi-domain
• Comparing other technologies
• Prototyping
• Verifying with real hardware
• Unified Software platform
• 1-10Gbps connections to end points
• 1 millisecond delay
• 1000x bandwidth
• 10-100x connected devices
• 99.999% availability
• 100% coverage
• 90% reduction in energy
• 10 year battery life for MTD
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Waveform Design Considerations for 5G
© Keysight Technologies 2015 6
Bandwidth /
Frequency
Waveform
New RAT
3GHz 6GHz 30GHz 90GHz
Advanced Multi-Carrier Waveforms1
OFDM FBMC / UFMC / Others Single carrier
>> Wider BW, Higher Fc, much sensitive at phase noise
Note1: • Orthogonal Frequency Division Multiplexing(OFDM)
• Filter Bank Multicarrier(FBMC)
• Universal Filtered Multicarrier(UFMC)
• Generalized Frequency Division Multiplexing(GFDM)
• Frequency Quadrature Amplitude Modulation(FQAM)
OFDMA NOMA SCMA
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Waveform Requirements
• Efficiently support high density users
• Optimized multiple access
• Carrier assignment schemes in asynchronous context
• Efficient usage of the allocated spectrum
• Robustness to narrow-band jammers and impulse noise
• High performance spectrum sensing
• Low computational complexity
• Compatibility OFDM vs. NEW
© Keysight Technologies 2015 7
Figure 1.
– OFDM vs. FBMC
Spectrum Using
different filter overlap
factor
Figure 2.
– FBMC Fragmented
Spectrum
Figure 3.
– UFMC multiplex of
sub-bands
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OFDM
Advantage
– Good spectral efficiency
– Resistance against multipath interference
– Efficiently implemented using FFTs and IFFTs
– Subcarrier nulls correspond to peaks of
adjacent subcarriers for zero inter-carrier-
interference
Drawback
– Some loss of spectral efficiency due to Cyclic
Prefix insertion
– Imperfect synchronization cause loss of
orthogonality
– Subcarrier intermodulation must be reduced
– High out-of-band power
– Large peak to average power ratio(PAR) leads to
amplifier inefficiency
© Keysight Technologies 2015 8
frequency
f1 f2
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Different Type of Waveforms and Filter Operation
© Keysight Technologies 2015 9
^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^ ^
UFMC
OFDM
FBMC
/GFDM
per sub-band
per full-band
per sub-carrier
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UFMC - Universal Filtered Multi-Carrier
© Keysight Technologies 2015 10
* OFDM can be implemented by set L as 1
x
+
x
.
.
.
.
.
.
x x
x x
P/S , IFFT Sub-band block
filtering
Figure 1.
Five sub-band multiplexed
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GFDM – Generalized Frequency Division Multiplexing
© Keysight Technologies 2015 11
x
+
.
.
.
.
.
.
x
x
Complex
subcarriers
.
.
.
x
Circular convolution implementation in frequency domain
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What is Problem Being Solved?
© Keysight Technologies 2015 12
IFF
T
P / S
S / P
FF
T
Sym
bo
l
ma
pp
ing
Sub-c
arr
ier
ma
pp
ing
Sub
-ca
rrie
r
de-m
ap
pin
g
Sym
bo
l
de-m
ap
pin
g
OFDM baseband signal processing blocks
High adjacent channel power ratio(ACPR)
FBMC baseband signal processing blocks
OQ
AM
pre
pro
cessin
g
IFF
T
Po
ly P
ha
se
Ne
two
rk
P / S
S / P
Po
ly P
ha
se
Ne
two
rk
FF
T
OQ
AM
p
ost p
roce
ssin
g
Synthesis Filter bank Analysis Filter bank
Sym
bo
l
ma
pp
ing
Sub-c
arr
ier
ma
pp
ing
Sub
-ca
rrie
r
de-m
ap
pin
g
Sym
bo
l
de-m
ap
pin
g
High peak-to-average power ratio(PAPR)
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FBMC Signal Processing Block
© Keysight Technologies 2015 13
Staggering Transform Poly phase
filtering
P/S
Conversion
.
.
.
x
x
x
.
.
.
x
x
x
.
.
.
.
.
.
.
.
.
x +
+ x
x
x
x
x
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
S/P
Conversion
Poly phase
filtering Transform De-
staggering
Sub
channel
processing
OQAM pre-
processing Synthesis Filter Bank Analysis Filter Bank OQAM post-
processing
FBMC transmitter FBMC receiver
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OQAM Preprocessing
© Keysight Technologies 2015 14
+
+
x
x
• A time offset of half a QAM symbol period(T/2) is applied to either the real part or the
imaginary part of the QAM symbol
• For two successive sub-channels, say m and m+1, the offset are applied to the real part of
the QAM symbol in sub-channel , while it is applied to the imaginary part of the QAM
symbol in sub-channel m+1.
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Synthesis Filter Bank
© Keysight Technologies 2015 15
x +
+ x
x
x
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
* Filter overlap factor K : number of multicarrier symbols which
overlap in the time domain.
* OFDM can be implemented by set K as 1
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Sub-channel Equalization
© Keysight Technologies 2015 16
Maximal ratio combined diversity reception
X X
+
X
+
transmitted symbol
Channel
Estimation H[z]
3-tap Complex FIR frequency sampling-design
Evaluation of MRC weighted target values
distorted subcarrier
sequence
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End to End Performance Simulation Model
© Keysight Technologies 2015 17
Simulation parameters
ChannelOut
Taps
ModelType=Pedestrian_A
C1 {CommsChannel@Data Flow Models}
• • •• • •
• • • • • •
MAPPER
ModType=QPSK [ModType]M1 {Mapper@Data Flow Models}
1 1 0 1 0
B1 {RandomBits@Data Flow Models}
DeMod IAmp
FreqPhase
Q
FCarrier=1e9 Hz
OutputType=I/Q D3 {Demodulator@Data Flow Models}
• • •• • •
• • • • • •
DEMAPPER
Bits
Node
ModType=QPSK [ModType]D2 {Demapper@Data Flow Models}
FBMC_Source
FBMC_Source_1
Re
Im
C4 {CxToRect@Data Flow Models}
ModOUT
QUADOUT
FreqPhaseQ
IAmp
M2 {Modulator@Data Flow Models}Re
Im
R3 {RectToCx@Data Flow Models}
NoiseDensity
NDensity=10e-12 W [NDensity]
NDensityType=Constant noise density A1 {AddNDensity@Data Flow Models}
FBMC_Receiver
FBMC_Receiver_2
O1 {Oscillator@Data Flow Models}
Random
bit
generation
Symbol
Mapping
FBMC
Reference
Source
LO source
Phase/
Power
Modulator
FO,IQ Im
Wireless
Channel
AWGN
Demodulator
FO,IQ Im
FBMC
Reference
Receiver
BER/FER
Measurem
ent
TEST
REF
BERFER {BER_FER@Data Flow Models}
ADC
Jitter /
Q noise
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C++ Models for Faster Simulation
© Keysight Technologies 2015 18
Algorithmic reference to convert
synthesizable fixed point model
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Case Study: Cross Domain Modeling & Simulation
© Keysight Technologies 2015 19
IP1dB=8 dBm [TXIFATTIP1dB]
L=6 dB10 [TXIFATTG]
Attn_2 {ATTN_NonLinear}
NF=5 dB [TXIFAMPNF]
G=7 dB [TXIFAMPG]
RFAmp_3 {RFAMP}
Fhi=8500 MHz [FTXIF+1500]
Flo=5500 MHz [FTXIF-1500]
N=3
IL=0.01 dB10
BPF_Butter_3 {BPF_BUTTER}
NF=8.85 dB [TXPANF]
G=20 dB [TXPAG]
RFAmp_4 {RFAMP}
IP1dB=100 dBm [TPAKIP1dB]
L=0 dB10 [TXPAKG+1]
Attn_1 {ATTN_NonLinear}
Fhi=29 GHz
Flo=27 GHz
N=5
IL=0.01 dB10
BPF_Butter_7 {BPF_BUTTER}
ZO=50 Ω
TRANSMITTERROUT {*OUT}
RI
L
LO=7 dBm
ConvGain=0 dB10 [TXRFMIXERG]
Mixer_3 {MIXER_BASIC}
Pwr=7 dBm
F=21000 MHz [3*FTXIF]
LO4 {PwrOscillator}
Source1=Wide: FTXIF MHz at -12 dBm, BW: 1000 MHz
PORT=1
TX_IF_IN {MultiSource}
Baseband Time Domain
Re
Im
C4 {CxToRect@Data Flow Models}
Power=0.01 W
Frequency=7e+9 Hz [FTXIF*1e6]
O1 {Oscillator@Data Flow Models}
ModOUT
QUAD
OUT
Freq
Phase
Q
I
Amp
FCarrier=7e+9 Hz [FTXIF*1e6]
InputType=I/Q
M2 {Modulator@Data Flow Models}
Spectrum Analyzer
ResBW=10000 Hz [RBW]
Start=0 s
Mode=ResBW
SPECTRUM_BB {SpectrumAnalyzerEnv@Data Flow Models}
RF_Link
SYS
CalcPhaseNoise=NO
EnableNoise=NO
FreqSweepSetup=Automatic
Schematic=TX_RF
Subnetwork1 {RF_Link@Data Flow Models}
CCDF
Stop=2e-2 s
Start=0 s
Distribution_FBMC {CCDF_Env@Data Flow Models}
• • •• • •
• • • • • •
MAPPER
ModType=64-QAM [P.FBMC.ModType]
M1 {Mapper@Data Flow Models}
1 1 0 1 0
DataPattern=PN15
B2 {DataPattern@Data Flow Models}
Spectrum Analyzer
ResBW=10000 Hz [RBW]
Start=0 s
Mode=ResBW
SPECTRUM_RF {SpectrumAnalyzerEnv@Data Flow Models}
FBMC_Source
ZC_RootIndex2=150
ZC_RootIndex1=350
FilterBankStructure=PPN_IFFT
FilterCoef=(1x4) [1,-0.972,0.707,-0.2…
FilterOverlapFactor=4
PilotEnable=NO [P.FBMC.PilotEnable]
ActiveSubcAlloc=(1x2) [-750,749]
NumSubcarriers=2048 [P.FBMC.NumSubcarriers]
NumDataSyms=24 [P.FBMC.NumDataSyms]
NumPreambleSyms=6 [P.FBMC.NumPreambleSyms]
IdleInterval=0 s [P.FBMC.IdleInterval]
OversampleRatio=Ratio 1
SampleRate=680e+6 Hz [P.FBMC.SampleRate]
FBMC_Source_1 {FBMC_Source@5G Advanced Modem BEL Models}
RF Frequency Domain
Specification:
• Fc = 28GHz
• Fs = 680MHz
• nFFT = 2048
• BW = 500MHz
• Mod = 64QAM
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Case Study Continue:
© Keysight Technologies 2015 20
Develop New Clipping Techniques using Realistic RF Models
FBMC Baseband Spectrum FBMC RF Spectrum without PAPR Reduction
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Moving from Simulation to Hardware in the loop
© Keysight Technologies 2015 21
RFIC DUT
• Wider BW (63 GHz BW)
• Higher Sampling (160 GSa/s)
BBIQ - RF
RF - BBIQ
M8190A 12 GSa/S Arbitrary
Waveform Generator
M9703A AXIe 12-bit High-Speed
Digitizer/Wideband Digital Receiver
Interleaving to get 4ch @ 3.2 GSa/s
Infiniium 90000 Q-Series Oscilloscope
I
Q
I
Q
SYSTEMVUE
TEST
REF
BERFER {BER_FER@Data Flow Models}
BPSK, QPSK, ..., up to 4096-QAM
8-PSK, 16-PSK, 16-APSK, 32-APSK16-Star QAM, 32-Star-QAM,
and Custom APSK
Data PayloadPreambleIdle
Frame Structure
Spreading CodeGenerator
X
Digital Modem Sourcefor Linear Modulation
DSSS System
Payload_ModType=16-QAM [Payload_ModType]
Preamble_ModType=BPSK [Preamble_ModType]
Decision Device
FeedwardFilter
-
-
FeedbackFilter
Decision Feedback Equalizer
Fast Computation Algorithm
CIR--->DFE coefficients
Digital Modem Receiver
TrackingAlgorithm=LMS
FreqSync_Mode=CIR Corr
FrameSync_Algorithm=DiffCorr
{DigMod_ReceiverL_FastDFE}
Automatic waveform
creation & download
Reference Source
Reference
Receiver
BER/FER Measurement
Custom modem
design
5G Reference
Library
: Replaceable
in C++, .m or
SV DSP
parts formats
Part II. What do you need for mmWave MIMO radio channel study?
Keysight EEsof EDA
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MIMO Fading Channel
© Keysight Technologies 2015 23
How much we know this in higher frequency?
time
frequency
Delay spread
• Frequency selectivity
• Coherence bandwidth(Bc)
Doppler spread
• Time selectivity
• Coherence time(Tc)
Angular spread
• Spatial selectivity
• Coherence distance(Dc)
mnmn
stxmnurxmn
mnHstx
mnVstx
HHmnHVmn
VHmnVVmn
T
mnHurx
mnVurxM
m
nsu
tj
rjrj
F
F
aF
FtH
,,
,,
1
0,,
1
0
,,,
,,,
,,,,
,,,,
,,,
,,,
1
,,
2exp
2exp2exp
;
* Tx antenna element s to Rx element u for cluster n
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Channel Sounding / Parameter Extraction / Simulation
© Keysight Technologies 2015 24
Reference transmit signal(chirp/pn)
channel
H[z] ∑ CIR
correlation
Channel
impulse
response
Channel sounding
Estimation
algorithms
Channel
parameters
• PDP (Path delay, path loss)
• AOA, AOD
• Doppler shift
Parameters estimation
• Scenario selection
• Network layout
• Antenna parameters
Large/Small scale
parameters
generation
Fading coefficient
generation
• AS AoA/AoD
• PAS
• Doppler spectrum
• Correlation
• Rician K factor
Statistics & modeling
¤ Input signal faded signal
SystemVue Simulation
SAGE
Maximum likelihood
estimation algorithm
No limitation for number
of path, suitable for both
LOS and NLOS scenarios
Can estimate all the
channel parameters
including path loss and path
delay of each path
Iteration needed, large
computing amount
ESPRIT
Subspace based algorithm
Maximum estimating
number of path is limited by
number of Rx, will be fail
under NLOS scenario
cannot estimate path loss
and path delay
small computing amount
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Requirements and Challenges
System Requirements
– Spatial consistency and mobility
– Diffuse versus specular scattering
– Very large antenna arrays
– Frequency range
– Complexity vs. Accuracy
– Applicability of the existing and proposed
models on the 5G requirements
Technical Challenges
– Channel measurement methodology
– High frequency instrumentation
– Ultra-broad band signal
– Synchronization and calibration
– Data streaming
– Channel parameter estimation process
© Keysight Technologies 2015 25
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Proposed Architecture / System Considerations
© Keysight Technologies 2015 26
Wideband Arbitrary
Waveform Generator
mmWave Vector Signal
Generator
Wideband Multi-channel
Digitizer
mmWave Multi-channel
Downconverter
mmWave Switch
mmWave
Signal
Wideband I/Q
mmWave
Sounding
Signal
IF Signal
LO: Precision Rubidium Clock
External
AWG
Acquisition
Trigger
Multi-channel Calibration
Power Calibration
System Impulse Response Calibration
Antenna Calibration
I/Q mismatch
correction
LO: Precision Rubidium Clock
Sounding technique • Sliding correlator
• Swept frequency
• Wideband correlation
MIMO capability • Switching @ Tx & Rx
• Parallel Rx & Rx
• Switching @ Tx, parallel Rx
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Data Capture and Streaming Considerations
© Keysight Technologies 2015 27
t1 t2
Note: • 1GSa/s sampling rate,
• Tp = transmitting period, Ts = transmitting signal length, Td = max delay spread
• PCI express 2.0 bandwidth(x16 lane) = 64Gbit/s(8GB/s)
Tp = 100 us
Ts = 20 us Td = 5 us
Td = 5 us
Effective Raw Data
Raw Sounding Data
Effective CIR Data
Tp = 100 us
Ts = 20 us Td = 5 us
Effective Raw Data
t3
Td = 5 us
CIR: Channel Impulse Response
Effective CIR Data
32GB/s
8GB/s
1.6GB/s
Reference Signal ¤ Real time implementation
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Prototyping and Testing in Real Time Hardware
© Keysight Technologies 2015 28
FPGA
ARRAY M9703
REAL-TIME PROCESSING
Up to 40 Channels x 1GHz wide
CUSTOM
ALGORITHMS
FPGA
ARRAY
– Move forward from largely theoretical massive MIMO research to real hardware
implementation and test
– Open FPGA and download custom algorithms for MIMO and Beamforming
– Test and measure in real-time (ex: channel sounding)
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Parameter Estimation Algorithms
© Keysight Technologies 2015 29
Algorithm Consistency Coherent
Signals
Estimation
Performance Computations
Max Num. of
Path
Beamforming
Based
Bartlett L=1 No Poor 1-D search
Capon No No Poor 1-D search
Subspace
Based
MUSIC1 Yes
No;
Yes for ROOT-
MUSIC
Good EVD,
1-D search < Num. of Rx
ESPRIT2
Yes
No;
Yes for TLS-
ESPRIT and
Unitary-ESPRIT
Good EVD < Num. of Rx
ML Based SAGE3
Yes Yes Good
Iterative,
1-D search No limitation
1MUSIC: MUltiple SIgnal Classification 2ESPRIT: Estimating Signal Parameter via Rotation Invariance 3SAGE: Space-Alternating Generalized Expectation maximization 4EVD: Eigen-Value Decomposition
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Case Study: Interact between Ray Tracing Fading Engine
– Stochastic channel models fail to accurately represent real-world environments
– Idea: replicate real-world scenes in lab. The scenes originate from
– Measurements (sounder, scanner, UE);
– Ray-tracing simulation software integration.
– System model
© Keysight Technologies 2015 30
2x2 transmitter 2x2 receiver
Custom ray tracing simulation software
Part III. Multi-Antenna Techniques
Keysight EEsof EDA
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Motivation
– Higher requirement for system capacity and spectral efficiency(bits/s/Hz)
– To overcome traditional approaches ( expand bandwidth, higher modulation order,
multiple access)
– The MIMO for better use the spatial resource
• The capacity is increased by a multiplication of the number of antennas
© Keysight Technologies 2015 32
MsbitN
SBC
/1log2
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Classification
© Keysight Technologies 2015 33
Spatial diversity
Improve robustness
Transmit Diversity Receive Diversity
Space-time block coding (STBC)
X1, X2
-X2, X1*
y1, y2
Spatial division multiplexing
Transmit Beamforming
Spatial multiplexing
Improve user throughput
MIMO
Matrix
X1
X2
y1
y2
Spatial Expansion
Multi-user MIMO
Multi-user Increase system
efficiency
Multi streams/users
.
.
.
.
.
. M a
nte
nn
as
K te
rmin
als
S s
tre
am
s
Massive MIMO
M >> K >> 1
Massive multi-users
Use spatial channel
information? • Open-loop MIMO
• Closed-loop MIMO
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Transmit Diversity
– Use transmit diversity to diminish the effects of fading by
transmitting the same information from two different
antennas
– The data from the second antenna is encoded differently
to distinguish it from the primary antenna
– The transmit diversity feature uses ST(space-time) or
SF(space-frequency) block encoding to differentiate the
signals between Antenna 1 and Antenna 2
– The user equipment (UE) must be able to recognize that
the information is coming from two different locations and
properly decode the data.
© Keysight Technologies 2015 34
X1, X2
-X2, X1*
y1, y2
** 12
21
xx
xx
f1 f2
t1 t2
Tx0
Tx1
SFBC:
STBC:
* complex conjugate
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Spatial Multiplexing
– Operation Concept
• Transmission of multiple spatial data streams over
different antennas in the same RB
• The dimension of spatial channels is increased and
system capacity increased
– Relevant signal processing
• Perform Layer mapping and Pre-coding to lower the
receiver complexity and reduce the signal interference
between antennas
• Statistic correlation between vector(h11,h12) and
vector(h21,h22 )
© Keysight Technologies 2015 35
X1
X2
y1
y2
h11
h21
h12
h22
x: transmitted signal,
y: received signal,
H: spatial channel matrix,
Hij: channel coefficient from the jth transmit
antenna and the ith receive antenna.
y=Hx
y1=h11x1+h12x2+n1
y2=h21x1+h22x2+n2
Page
Modeling and Simulation for MIMO
– MIMO Tx/Rx simulation under Rayleigh fading and AWGN channel
– Explore different decoding algorithms and performance evaluation
• ML, MMSE-SIC, ZF-SIC, MMSE-Linear, ZF-Linear
© Keysight Technologies 2015 36
A4 {Add@Data Flow Models}
StdDev=707.1e-6 V [StdDev]I2 {IID_Gaussian@Data Flow Models}
StdDev=707.1e-6 V [StdDev]I6 {IID_Gaussian@Data Flow Models}
Re
Im
R1 {RectToCx@Data Flow Models}
[ ]
Format=ColumnMajor NumCols=1 [RxNumCols]
NumRows=2 [RxNumRows]P2 {Pack_M@Data Flow Models}
[ ]
Format=ColumnMajor NumCols=1 [TxNumCols]
NumRows=2 [TxNumRows]
U1 {Unpack_M@Data Flow Models}
MIMO_DecoderRec ov eredData
M odType
ChannelRes ponse
Rec eiv edData
DebugFlag=0
ModType=QPSK [ModType]DecoderMethod=ML [DecoderMethod]
Mode=Spatial Multiplexing [Mode]M3 {MIMO_Decoder@5G Advanced Modem Models}
• • •• • •
• • • • • •
DEMAPPER
Bits
Node
ModType=QPSK [ModType]D1 {Demapper@Data Flow Models}
M2 {Mpy@Data Flow Models}
StdDev=0.707 V [1/sqrt(2)]I5 {IID_Gaussian@Data Flow Models}
Re
Im
R3 {RectToCx@Data Flow Models}
[ ]
Format=ColumnMajor
NumCols=2 [ChannelNumCols]NumRows=2 [ChannelNumRows]
P1 {Pack_M@Data Flow Models}
StdDev=0.707 V [1/sqrt(2)]I7 {IID_Gaussian@Data Flow Models}
MIMO_Encoder
NumTx=2 [NumTx]Mode=Spatial Multiplexing [Mode]
M1 {MIMO_Encoder@5G Advanced Modem Models}
[ ]
Format=ColumnMajor NumCols=1 [TxNumCols]
NumRows=2 [TxNumRows]P3 {Pack_M@Data Flow Models}
• • •• • •
• • • • • •
MAPPER
ModType=QPSK [ModType]
M5 {Mapper@Data Flow Models}
1 1 0 1 0
B2 {RandomBits@Data Flow Models}
Fading Channel AWGN
Transmit with MIMO coding MIMO decoding and demapper
Page
Multi-User MIMO
© Keysight Technologies 2015 37
Received signal at UE k:
The challenge for MU-MIMO is to find orthogonal
users and design precoding W to minimize the
second term with the restrictions of user grouping,
power, latency and complexity
Hk: kth user’s channel, Wk: weight vector, Sk: data symbol
Capacity Comparison
MU-MIMO Scenario
Page
Modeling and Simulation for Capacity Estimation
© Keysight Technologies 2015 38
Simulation condition
– Transmit antenna number (M) : 4
– Total number of user : from 4 to 100
– SNR=10dB
– Power allocation by waterfilling algorithm
User Scheduler
Power_Selected
W_Selected
H_Selected
H
TotalPower=10 [SNR]
NumRx=1
NumTx=4 [NumTx]
TotalUsers=100 [TotalUsers]
UserScheduler {MATLAB_Script@Data Flow Models}
Channel Capacity
R
P
W
H
NumRx=1
Noise=1
NumTx=4 [NumTx]
SumRate {MATLAB_Script@Data Flow Models}
NumInputsToAverage=100
A1 {Average@Data Flow Models}
123
StartStopOption=Samples
S4 {Sink@Data Flow Models}
StdDev=0.707 V [1/sqrt(2)]
I1 {IID_Gaussian@Data Flow Models}
StdDev=0.707 V [1/sqrt(2)]
I3 {IID_Gaussian@Data Flow Models}
Re
Im
R2 {RectToCx@Data Flow Models}
[ ]
Format=ColumnMajor
NumCols=4 [NumTx]
NumRows=1 [NumRx]P4 {Pack_M@Data Flow Models}
BlockSize=1
D2 {Distributor@Data Flow Models}
Channel transfer matrix User scheduling Capacity measurement
User K: 4->100
Su
m C
ap
acity
Page
Massive MIMO
– The use of a very large number of service antennas operated fully
coherent and adaptive
– Brings huge improvements in throughput and energy efficiency
when combined with simultaneous scheduling of a large number of
UEs
– System Model : M transmit antenna with maximum S streams, K
users each with a single antenna
– Originally envisioned for time division duplex(TDD1), but can
potentially be applied in frequency division duplex(FDD)
© Keysight Technologies 2015 39
.
.
.
.
.
. M a
nte
nn
as
K te
rmin
als
S s
tre
am
s
Massive MIMO
M >> K >> 1
Massive multi-users
Note1 : Prefer TDD as not enough resources for pilots and CSI feedback.
Page
Massive MIMO Operation and Challenges
Operation
– Acquire Channel State Information from uplink
Pilots / Data
– Reciprocity calibration and adjustment
– Pre-coding1 to support multi-stream
transmission
– MMSE receiver with beamforming
• Maximum ratio combining(MRC) : interference
and noise are both white in the space
• Interference rejection combining(IRC): colored
interference
Challenges
– Pilot contamination: interference from other cells
• Blind channel estimation?
• Coordination and planning?
– New pre-coder with low-complexity, low-PAPR
– Hardware performance
• I/Q imbalance, A/D resolution, PA linearity
• Phase noise, clock distribution
– Synchronization at low SNR
© Keysight Technologies 2015 40
Note1 : Linear pre-coding [maximum ratio transmission(MRT), zero-forcing(ZF)].
Non-linear pre-coding [Dirty paper coding(DPC)], full CSI required
Page
Modeling and Simulation for Large Number of Antennas
© Keysight Technologies 2015 41
quad_output
output
LO
inputMultiChannel
Modulator
ShowIQ_Impairments=NO MirrorSignal=NO
ConjugatedQuadrature=NO AmpSensitivity=1 [[1]]
InitialPhase=0 ° [[0]]FCarrier=1e6 Hz
NumChannels=1 M1 {MultiCh_Modulator@5G Advanced Modem Models}
TxBeamformer
weights
output
InPhi
InTheta
input
Phi=0 °Theta=0 °
Dy=0.5 Dx=0.5
NumOfAnty=4 NumOfAntx=4
BeamformingType=Calculate by antenna … T1 {Tx_Beamformer@5G Advanced Modem Models}
Env
OutputFc=Center
M4 {MultiCh_AddEnv@5G Advanced Modem Models}
MultiChNoise Density
NDensity=0.0 WNDensityType=Constant noise density
M6 {MultiCh_AddNDensity@5G Advanced Modem Models}
MultiChannel
Demodulator
ShowIQ_Impairments=NO MirrorSignal=NO
AmpSensitivity=1 [[1]]InitialPhase=0 ° [[0]]
FCarrier=1e6 HzNumChannels=1
M2 {MultiCh_Demodulator@5G Advanced Modem Models}
RxBeamformer
weights
output
ref
input
BlockSize=1024 ABF_Algorithm=Sample Matrix Inversion
NumOfTxAnts=16 R1 {Rx_Beamformer@5G Advanced Modem Models}
Power=.010 WFrequency=1000000 HzO1 {Oscillator@Data Flow Models}
Transmit
Beamformer
Multi-CH
Modulator
Multi-CH
Envelope Adder
Multi-CH
AWGN Multi-CH
De-Modulator
Receive
Beamformer
Page
Summary: What you need for your 5G research is…
© Keysight Technologies 2015 42
Transition naturally from Design to Test with a single “cockpit”
Unified
Platform
Software
Quickly capture “system level”
design concepts
Model implementation-level
impairments
Connect BB, RF, and T&M
for rapid validation
Rapid prototyping with
integrated measurement
RF / Analog
Channel Modeling MIMO Channel (OTA)
Digital Pre-Distortion (DPD)
RF System Design
Test Equipment RF Sources & Analyzers
AWG & Digitizers
Scopes, Logic, Modular
Test Software I/O Lib, ComExpert
89600 VSA
Signal Studio
3rd Party
BB Algorithm
Modeling MATLAB .m
FixedPoint, HDL/FPGA
Embedded C++
Filtering, EQ, Modem
IP Reference Libraries 4G LTE-Advanced, LTE ,5G
3G HSPA+, WCDMA, EDGE, GSM
WLAN 802.11ac/n/a/b/g
WPAN 802.11ad, 802.15.3c
RF EDA
Platforms
Model Based Design
Mixed Simulation
Technologies
5G Reference IP
Page
Thank you!
– Resources
• SystemVue : www.keysight.com/find/eesof-systemvue
• 5G Library: www.keysight.com/find/eesof-systemvue-5g-exploration
–Try SystemVue! Obtain a “FREE” 45-day evaluation copy of SystemVue and
explore how SystemVue can help with early 5G systems exploration and evaluation
• http://www.keysight.com/find/eesof-systemvue-evaluation
© Keysight Technologies 2015 43